The excitatory amino acid, glutamate, is cleared from the synapse by a family of glutamate transporters. EAAC1, a neuronal subtype, is enriched in the hippocampus and cortex, areas that are extremely sensitive to excitotoxic insults. EAAC1 subcellular localization is regulated by stimulation in C6 glioma cells. PDGF has been shown to be neuroprotective, and regulation of EAAC1 may represent one way in which PDGF exerts its neuroprotective effects. The goal of this proposal is to understand the mechanisms underlying PDGF-dependent regulation of EAAC1. Aim I is to determine if PDGF-dependent phosphorylation of the proto-oncogene product, Cbl, via an interaction with the Cbl adapter protein (CAP) is required. This will be examined by expressing a dominant interfering CAP construct and measuring cell surface EAAC1 expression after PDGF treatment. Aim II is to test whether intact actin filaments are required for stimulated trafficking, by pre-treating cells with an actin depolymerizer and measuring glutamate uptake and cell surface EAAC1. Aim Ill is to identify structural motifs of EAAC1 required for PDGF-dependent trafficking, using chimeras and mutant variants of EAAC1. [unreadable] [unreadable]